The task force assembling Virginia's court cases against John Allen Muhammad and John Lee Malvo ended a series of briefings about each of the sniper shootings yesterday, marking the conclusion of the transfer of most of the evidence to prosecutors.

Investigators from Virginia, Maryland and the District and the FBI and Bureau of Alcohol, Tobacco and Firearms have shared information and evidence over the past two weeks in individual meetings about each of the sniper shootings in the Washington area and attacks in Montgomery, Ala., and Atlanta that have been linked to the suspects. The meetings in the task force's new Centreville offices were orientation sessions for the officials prosecuting Muhammad and Malvo in Prince William and Fairfax counties.

"An awful lot of work has been done, and an awful lot of work remains to be done," said Paul B. Ebert, commonwealth's attorney in Prince William, where Muhammad is charged with two counts of capital murder. "There's an extended effort to glean all of this evidence, and there's a lot of information out there."

The prosecution task force -- now whittled to a few dozen local, state and federal agents -- has been working round-the-clock to investigate the 21 shootings that are believed to be part of a series of attacks that stretched from the Pacific Northwest to the Deep South to the District. Muhammad and Malvo are charged in 13 shootings -- 10 of them fatal -- in the terrifying Washington area sniper attacks in October, and are suspected in eight other shootings across the country. They were arrested at a Maryland highway rest stop Oct. 24 as they slept in the dark blue Chevrolet Caprice they allegedly used in many of the shootings.

Authorities in Prince William and Fairfax said yesterday that they are pleased with the progress, but they declined to discuss specific evidence. Fairfax County police declined to comment.

Work over the past few weeks has focused on transferring and sharing evidence and speaking with potential witnesses.

"We're reviewing all the evidence in close coordination with the prosecutors," said Prince William Police Chief Charlie T. Deane. "This is a murder case that is a local murder case, and we're preparing it as such, keeping in mind the relationship this case has to all the other cases."

The center of the probe now is in Centreville -- about halfway between the Prince William and Fairfax courthouses. Task force members often gather there to go over sensitive information before dispersing to chase any promising leads, said James A. Willett and Richard A. Conway, assistant commonwealth's attorneys in Prince William, who, with Ebert, are leading the investigation there. Virginia authorities now have access to all of the physical evidence gathered from the various crime scenes. Having such evidence -- the car, the rifle they say was used, the letters written by the snipers -- is critical to prosecutors.

"It's a process of accumulating what evidence you're going to need," said Robert F. Horan Jr., the chief prosecutor in Fairfax, where Malvo is charged with two counts of capital murder. "There's an awful lot of evidence out there that may be of use in some cases and not in other cases. It's a process of sorting it out."

Horan said prosecutors have received nearly all the evidence and are immersed in the lengthy process of culling it.

Prosecutors are visiting the Centreville office almost daily. "There are [a] lot of curious minds there," Willett said. "I feel I have a much better notion of this saga front to back than I had before. This situation was so unique that I had very few preconceived notions going in. There haven't been any surprises because there aren't any expectations."

As prosecutors assemble their cases, defense attorneys say that they, too, will have to go to extraordinary lengths. While Muhammad's attorneys said they don't want to discuss trial strategy, Peter D. Greenspun said he will most likely have to match and even exceed the scope of the government's investigation.

Todd D. Petit, Malvo's court-appointed guardian, said he is tracking down information about Malvo's background for a report to be presented to a Fairfax Juvenile and Domestic Relations Court judge before a Jan. 14 preliminary hearing that will determine whether Malvo is tried as an adult and faces the death penalty.

Petit said he has learned some details from Malvo's mother, Una James, who is in Seattle awaiting deportation to Jamaica. "She is very concerned about her son," Petit said. "She has been helpful in leading me to information that I think is very important, and people will need to know about her son."

Petit said James has not been able to speak to Malvo. Last month, federal immigration officials ordered her deported.

Muhammad is scheduled to appear in Prince William County Circuit Court tomorrow to set a date for the trial and for arguments about whether television cameras will be allowed to broadcast it.

A number of television outlets have asked the court to allow a broadcast of the trial, arguing that the public has a right to see proceedings dealing with shootings that affected so many people.

Greenspun filed a memo with the court Friday opposing television cameras, saying that such coverage would be disruptive and could jeopardize the fairness of Muhammad's trial. "Can anyone maintain that the televising of the O.J. Simpson case did not impact the prosecution, defense witnesses and court?" Greenspun wrote. Ebert also opposes TV cameras.

Also this week, Fairfax officials said they will join Prince William in seeking federal funds to offset the cost of the high-profile prosecutions. Prince William officials said yesterday that the investigation already has cost $426,000.

Staff writers Steven Ginsberg and Leef Smith contributed to this report.

John Lee Malvo, left, and John Allen Muhammad are charged with two counts each of capital murder.